Wider spread of evolution item drops

Hello folks!

I've encountered a certain problem rather often during Region stories. Let me take the latest example. During my Sinnoh run, I captured a Clefairy in Mt. Coronet to use in my story team. And later on during the story, I've noticed: I did not have a Moon Stone (my last one disappeared during the quest to unlock the region). So I've looked and discovered that there exists no way to obtain a Moon Stone in Sinnoh. In other words, unless someone delivers me a Moon Stone from another region, it is impossible to evolve my Clefairy until I finish the Sinnoh story, at which point I won't want to evolve it anymore.

Fortunately, I had a guild to back me up, but this is rather frustrating. Three of the pokemons I chose for my Sinnoh story required an item that cannot be obtained during the Sinnoh story, namely Moon Stone, Sun stone and Razor Fang. Those don't seem to be the only cases.

So I suggest that all evolution items be available in all regions following the rule: If an evolution item can be obtained in a previous region and is required by a pokemon in the current region, it must be possible to obtain it during the story of that region before completing the 7th badge. This means I consider it fine that Gligar's Razor Fang is not found in Kanto, but not fine that it is not found in Sinnoh when it could be found in Johto and Hoenn.

The way they are made available does not matter too much, although diggable spots are not preferred: the 3 days cooldown for retry makes it better to just abandon the pokemon. The item could be a rare held item, or it could be a one-time quest reward. As long as it is possible to take a small break from the story and farm for the item.